(1) Field of the Invention
The present invention relates to a photo interrupter in which a light-emitting element and a light-receiving element are disposed opposing each other to create an object passage whereby an object which passes therebetween is detected.
(2) Description of the Prior Art
FIG. 1 is a constructional example of a prior art photo interrupter. The construction of this photo interrupter will be explained in the following steps of the manufacturing procedure.
A light-emitting-side transparent resin part 60 is formed such that a light-emitting element, after mounted on a frame for a light-emitting element and bonded thereon, is molded with a light transmissive resin material. Similarly, a light-receiving-side transparent resin part 61 is formed such that a light-receiving element, after mounted on a frame for a light-receiving element and bonded thereon, is molded with a light transmissive resin material. A lead 60a from the light-emitting-side transparent resin part 60 and leads 61a and 61b from the light-receiving-side transparent resin part 61 are soldered on a print board 62 so as to form a passage 63 to allow an object to pass through. A connector 64 for electrically connecting the light-emitting element and light-receiving element with the outside is fixedly joined with solder 65 to the print board 62. After checking the soldering, the print board 62 is fitted into a casing 66 having hooks 66a and 66b in the bottom thereof. These hooks 66a and 66b are used to assure the fixing between the print board 62 and the casing 66 itself.
As stated above, many components, e.g. the light-emitting-side transparent resin part 60, the light-receiving-side transparent resin part 61, the print board 62, the connector 64 and the casing 66 as in the above case, have been required for such a conventional photo interrupter. For this reason, the prior art devices disadvantageously took much time and labor for assembling. Further, there were quite a few places to be soldered in assembling; therefore, examination of the soldering was required to maintain reliability and quality. Since the connection between the print board 62 and the connector 64 is supported by the strength of the solder, reliable and rigid soldering is required.
Further, fastenings with complicated structures such as hooks 66a, 66b were used for fixing, so that the fixing work not only took much time and labor but also posed a high likelihood of breaking.